This invention relates generally to lawn maintenance equipment, particularly to powered turf treatment devices used for aerating a lawn.
Thick green lawns require care. Such care includes consistent mowing, watering, dethatching, seeding and fertilization. In addition, aeration contributes significantly to the overall health of a lawn. Aeration is accomplished by creating a number of small holes in the ground surface designed to increase penetration of water, oxygen and nutrients while also providing receptacles for grass seed and nutrients thus preventing them from being washed away during watering or as a result of heavy rains. The increased ventilation resulting from aeration further enhances the decomposition process necessary to reduce thatch buildup.
The process of making holes in the turf with current machines is not an easy task and operators complain about the difficulty in using such units. Making turns with this type of unit is the most difficult part of the operation because the tines are imbedded into the ground and all of the powered tine wheels in known machines are either rotating at the same speed or the rotation of one half of the tines is completely stopped while the other half of the tines continue to rotate. When the tine wheels of this type of machine are in contact with the ground it is impossible to make a turn without damaging the turf, which is extremely undesirable in certain sites, such as on golf courses. The damage occurs as a result of the tines tearing the turf and because it is impossible to stop the drive rollers from sliding across the surface of the turf. As a consequence of the embedded tines, the operator must exert a great deal of effort to turn the aerator.
Current machines require that the tines of the unit be lifted out of the ground to put the machine on its transport wheels and into a non-operational position so a turn can be made more easily and without tearing up the ground. The process of lifting this type of machine into the transport position is accomplished only with a substantial amount of operator effort.
U.S. Pat. No. 6,102,129 to Classen discloses a turf aerator with two separate tine shaft halves that are driven by two separate drive mechanisms that must be operated either simultaneously or independently of one another. The disclosed aerator provides only for two alternative conditions with regard to the rotation of the tine shaft halves. Either the two tine shaft halves rotate simultaneously at the same rotational speed or the rotation of one of the tine shaft halves is stopped while the other tine shaft half continues to rotate, causing the aerator to turn in the direction of the stopped tine shaft half. The invention does not allow for the two tine shaft halves to rotate at different speeds relative to each other.
Operators complain that such machines are difficult to turn smoothly and unnecessary damage to the turf occurs because the tine shafts are in either a rotating or stopped configuration in these machines. Further, the drive rollers on these machines exhibit a sliding motion on the turf, resulting in unnecessary damage to the grass because the rotation of the roller on the inside of the turn must be stopped while the outside roller continues to rotate. Additionally, such machines currently have a single drive chain, located on either the right or left side of the machine with one side connected to the drum and the other side not connected to the drum, making it more difficult to turn in one direction than the other.
Current machines also require the addition of water in the drive rollers or other weighting methods to ensure that the machine is heavy enough for the tines to penetrate the turf. Present machines also require substantial effort and disassembly to service or change drive belts because the drive and reduction shafts must be removed to free the drive belt. Finally, operators often complain about the difficulty in changing current machines from the operational position, with the tines engaged in the turf, to the non-operational, transport position where the tines are elevated and the machine is positioned on transport wheels.
The present invention solves these problems.
An aerator that allows the operator to make a turn with the machine while the tines are still in contact with the turf through the use of a differential and brakes that enhance the maneuverability of the machine. The aerator is fitted with a mechanical gear type differential on an intermediate drive shaft that provides for automatic, separate and variable rotational motion of the individual halves of the tine shaft. This differential apparatus also provides constant and equal torque application to both sides of the tine wheel assembly simultaneously while the machine is operating. This insures that tine penetration into the turf is equal on both sides at all times. The tine shaft halves are designed and mounted in such manner as to allow each half (left and right sides) to be driven by separate chains from the differential shaft. This design results in a desired variation in the speed of rotation of the two halves that facilitates in turning the unit. The differential mechanism is also functional in driving the transport drive rollers at the front of the machine. The improved aerator is also fitted with brakes installed on each side of the unit, which can selectively reduce the speed of rotation of the separate tine wheel halves as well as the individual drive rollers on the front of the unit, thus increasing the steering efficiency.
The new aerator also includes a spring-actuated lift assist to help the operator raise the unit into the transport position. This mechanism consists of heavy duty springs on both sides of the unit to apply equal forces to both of the transport wheel lift members. A release mechanism operated from the handle bar is provided to allow the operator to disengage the retaining latches, which will allow these springs to pull the transport wheels forward and under the unit thus raising the tine shaft out of the turf. The aerator also incorporates drive rollers of sufficient mass such that the addition of water or other additional weighting methods is not required.
An object and advantage of the invention is to provide a powered walk-behind aerator with enhanced maneuverability and ease of operation by providing automatic, selective and variable power to each aerator tine shaft half and each drive roller.
Another object and advantage of the invention is to provide a powered walk-behind aerator with enhanced maneuverability due to the use of brakes that assist with the steering of the aerator.
Another object and advantage of the invention is to provide a powered walk-behind aerator with enhanced maneuverability during the aeration operation by providing selective power to each tine shaft half via two easily accessible drive chains from a differential shaft.
A further object and advantage of the invention is to provide a powered walk-behind aerator with enhanced maneuverability during both the aeration operation and transport by providing selective power to each drive roller via two drive chains from a differential shaft.
Another object and advantage of the invention is to provide a powered walk-behind aerator that reduces the amount of turf damage by minimizing the slipping or skidding of the drive rollers during the turning operation.
Yet another object and advantage of the invention is to provide a novel spring-assisted lifting mechanism for easily adjusting the aerator from an operative position wherein the aerator tines are positioned to allow engagement with the turf to a transport position wherein the aerator is in an inoperative position with the aerator tines raised to prevent engagement with the turf.
A further object and advantage of the invention is to provide a self-propelled aerator with drive rollers that do not require the addition of water or other weights in order to ensure the aerator tines penetrate the ground effectively.
Another object and advantage of the invention is to provide a method of manufacturing drive rollers from a suitable material such that they are of sufficient mass as to eliminate the need to fill the drums with water to facilitate the penetration of the tines in the ground surface.
Another object and advantage of the invention is to provide a differential shaft that includes an easily separable coupling, generally in the middle of the shaft, to allow for quick replacement of the drive belt and other maintenance thereon.
Yet another object and advantage is that the present invention substantially reduces the effort needed to lift the machine in order to get the tines out of the ground. Additionally, the present invention allows the operator to make a turn with the machine while the tines are still in contact with the turf through the use of a differential driving mechanism and brakes that enhance the maneuverability of the machine.
An object and advantage is that the present invention is fitted with a mechanical gear type differential on an intermediate drive shaft that provides for automatic, separate and variable rotational motion of the individual halves of the tine shaft. In order to make a turn easily, the tine shaft half on the inner portion of the turn must turn slower than the tine shaft half on the outer portion of the turn. This differential apparatus also provides constant and equal torque application to both sides of tine wheel assembly simultaneously while the machine is operating. This insures that tine penetration into the turf is equal on both sides at all times. The tine shaft halves are designed and mounted in such manner as to allow each half (left and right sides) to be driven by separate chains from the differential shaft. This design results in a desired variation in the speed of rotation of the two halves that facilitates turning the unit.
Another object and advantage is that the differential mechanism is also functional in driving the transport rollers at the front of the machine. During turns, whether aerating or transporting, the differential will automatically adjust the speeds of the roller segments to match the desired rotational speeds, which will limit the amount of sliding action on the turf thus reducing turf damage while making it easier for the operator to make these turns.
Yet another object and advantage is that the present invention is fitted with brakes installed on each side of the unit, which the operator can actuate to reduce the speed of rotation of the separate tine shaft halves and the individual drive rollers on the front of the unit, thus increasing the steering efficiency. This reduction in speed of rotation of the tine shaft halves and drive rollers allows the machine to make turns at a more reasonable speed because the tine shaft half on the inner aspect of the turn will slow down. The differential aspect of the invention occurs automatically in response to changes in terrain or pressure provided on the machine steering handle in a given direction by the operator. The steering operation may be assisted by the operator by means of dual control brakes located on the operational handle which are engaged as needed to make a turn to the right or to the left. The brakes can be band, disc, or other equivalent designs to effectively allow the operator to slow the rotational speed of one side of the differential shaft which drives the tine shaft halves and drive rollers to enhance the turning operation, thus allowing for smoother turns while limiting turf damage.
Another object and advantage is that the power to the tines and rollers can be quickly engaged and disengaged by activating or releasing the main drive clutch, which is controlled by the operator at the operational handle. This clutch is a simple idler pulley designed to engage the outer surface of the xe2x80x98Vxe2x80x99 belt when the operator actuates the clutch by pulling the operational handle towards the steering handle, thus tightening the belt around the engine power take-off pulley and the differential shaft pulley, causing the differential shaft to rotate.
Yet another object and advantage is that rolling aerators, such as being described herein, must have sufficient overall weight to penetrate the turf. The present invention accomplishes this, in part, through uniquely designed molded drums that do not require the addition of water to obtain the proper weight as is required with current aerators. The present invention also eliminates the need to load the aerator with additional weights or ballast thus providing superior handling and maneuverability.
Another object and advantage is that the present invention is equipped with a spring-actuated lift assist to help the operator raise the unit into the transport position. The present invention includes heavy duty springs on both sides of the unit to apply equal forces to both of the transport wheel lift members. A release mechanism operated from the handle bar is provided to allow the operator to disengage the retaining latches, which will allow these springs to pull the transport wheels forward and under the unit thus raising the tine shaft halves.